PROJECT SUMMARY A large number of studies of girls and women in sub-Saharan Africa (SSA), a region disproportionately affected by HIV, have found a link between intimate partner violence (IPV) victimization and HIV infection. One understudied explanation that has been put forth for this link is that male IPV perpetrators are more likely than non-perpetrators to engage in sexual risk behaviors putting both themselves and their partners at risk for HIV and other sexually transmitted infections (STIs). Consistent with this notion, a small but growing body of cross-sectional research with men and boys in SSA has demonstrated an association between IPV perpetration and sexual risk behavior. Yet, almost no research in SSA or other settings has gone beyond establishing an association to examine patterns of co- occurrence (comorbidity) across multiple dimensions of IPV and sexual risk and/or identify factors (or combinations of factors) that drive comorbid behavior patterns. This is a critical gap in the literature; understanding the intersection of various dimensions of IPV (e.g., psychological, physical, sexual) and sexual risk behavior (e.g., condom use, concurrency) among men can provide a more complete picture of different profiles of behavior common in the population. Further, identification of characteristics that predict membership in groups characterized by a profile of high-risk comorbid behavior has the potential to inform targeting of prevention resources. The objective of the proposed study is to identify and characterize the etiology, manifestation, and consequences of comorbid IPV perpetration and sexual risk behavior in a longitudinal cohort of 1,249 young men living in Dar es Salaam Tanzania who were assessed at two time points across a 33-month period. Drawing from the common factor model the overarching central hypothesis is that IPV perpetration and sexual risk behavior are rooted in the same risk factors including adverse childhood experiences, inequitable gender norms, and substance use. Further, drawing from resiliency and social control frameworks, it is posited that associations between individual risk factors and high (vs. low) risk IPV/sexual risk behavior profiles will be weaker among men with greater self-regulatory ability and among men nested in social contexts that constrain, rather than facilitate, risky behavior. To test these hypotheses person-centered analytic approaches will be used to: (1) identify subgroups of Tanzanian men involved in distinct profiles of IPV perpetration (psychological, physical, sexual) and sexual risk behavior (condom use, # of sexual partners, sexual partner concurrency) and examine links between profile membership and STI risk; (2) determine whether and how risk factors in three key domains--adverse childhood experiences (household dysfunction, family violence exposure), gender norms (inequitable gender role attitudes, masculine gender role stress), and substance use (heavy alcohol use, marijuana use)?distinguish IPV/sexual risk behavior profile membership and explain profile transitions over time; and (3) identify individual and contextual (peer, neighborhood) protective factors that buffer the influence of risk factors on profile membership. Findings will provide a nuanced and comprehensive view of comorbid patterns of IPV and sexual risk among men in a high-HIV prevalence setting, thereby informing the development of integrated strategies to prevent both behaviors in this key target population.